Today, virtualization of computing resources has been gaining popularity because of increased operational flexibility. Broadly speaking, virtualization is emulation of physical hardware. A virtual machine, thus, refers to generally a software implementation of a machine that executes programming instructions to perform operations and tasks as if executed by a physical machine, such as a personal computer. A virtual machine may be a virtual host or a virtual guest. In some conventional systems, the virtual host and the virtual guests are all virtual machines running under the hypervisor, which is a virtualization controller running on the physical machine. In some conventional systems, an operating system running on the physical machine acts as a host to one or more virtual guests.
Currently, users have to use various tools or procedures outside of a centralized server to install an operating system onto a physical machine, and then to install a virtualization controller, which is typically referred to as a hypervisor of the physical machine. Then the users may use the hypervisor to provision virtual hosts and virtual guests on the physical machine. On each of the virtual hosts and virtual guests, the user has to manually install a copy of the operating system, such as Linux, Windows, etc. In general, the user needs to have a license for each copy of the operating system installed on the physical machine, the virtual hosts, or the virtual guests. Note that the operating system on the virtual hosts and virtual guests may or may not be the same. As the number of physical machines and the number of virtual machines grow in a networked system, management of licenses and the physical machines and the virtual machines becomes more complex and tedious.